two along the canal and two near the newtown creek. the agency tested the newtown creek sites 13 days after the storm. the e.p.a. detected high levels of bacteria and some gasoline and diesel fuel. the agency declined requests for an interview but in a press release reported that other chemicals that were tested were below levels of concern or not detected. thomas burke of johns hopkins used to be the state of new jersey's chief environmental scientist. he says it appears the risk from sandy's flood waters are low but it's impossible to know the long-term risks of what may have been in the water without more extensive testing. >> does every single house have to be sampled? can we characterize what was in flood waters without doing that? probably. but we do need more samples. i think if i lived there, i'd want to know. >> reporter: burke says it's difficult for the e.p.a. to do a lot testing in the wake of disaster like sandy but he says testing is the only way to ameliorate the fears of flood zone residents like jacqueline lomb barred.